Place turkey carcass in a stockpot; add water, celery and onion. Slowly bring to a boil. Reduce heat; simmer, covered, 2 hours. , Remove carcass and cool. Strain broth through a cheesecloth-lined colander; discard vegetables. Skim fat. Remove meat from bones and cut into bite-sized pieces; discard bones. Return broth and meat to pot., Add beans, spinach, chopped onion, bouillon, salt and pepper. Bring to a boil. Reduce heat; simmer, covered, 10 minutes.